Electric starter for internal combustion engines



June 26, 1934. J. BETHENOD 1,964,310

ELECTRIC STARTER FOR INTERNAL COMBUSTION ENGINES Filed Jan. 2, 1931 fiseo/a Bef/ze 120a Patented June 26, 1934 PATENT OFFICE ELECTRIC STARTERFOB. INTERNAL COMBUSTION ENGINES Joseph Bethenod, Paris,

France, assignor to Societe De Paris Et Du Rhone, Lyon, France, a

corporation of France Application January 2, 1931, Serial No. 506,075 InFrance February 12, 1930 3 Claims.

It has been proposed, in particular for the starting of internalcombustion engines, to employ an electric motor operatively connected tothe shaft of the engine to be started by a transmission mechanism whichensures that once the starting is effected an automatic disengagement ofthe said transmission mechanism from the engine shaft is efl'ected. Itis known to use in particular in order to produce this effect,transmission mechanism including elastic means which are associated, onthe one hand with the shaft of the electric starting motor, and on theother hand, with a driving member arranged concentrically to said shaft.

The object of the invention is to provide improvements of said mechanismpresenting remarkable advantagesas regards the safety, durability,simplicity and economy. The invention relates more specifically to aform in which the elastic means employed consists of a helical springhaving serially disposed windings, affording flexible operation,efficient functioning and reduced size of constructionf Figures 1 and 2of the accompanying drawing disclose diagrammatically the constructionof an apparatus for carrying the invention into effect.

Refen'ing to the drawing, a shaft 1 of an electric starting motor (notshown) or a shaft of a reducing gear driven therefrom has a pinion2rotatably and slidably mounted thereon and arranged under the control ofa fork (not shown) which extends into a groove 3 formed in a boss on thepinion. A fiat spirally wound flexible strip 6 of a material such assteel, fibre or the like is arranged within a recess formed in thepinion at 4 so as to surround the shaft 1 with which it engages with arelatively slight degree of friction. One end '7 of the strip 6 is fixedto the pinion while the other end rests freely upon the shaft 1.

When it is desired to effect the starting of the internal combustionengine, the unit 2, 3, 6 is caused to slide along the shaft 1-, in suchmanner 45 that the pinion 2 meshes with a toothed crown wheel 5 keyed tothe shaft of the engine, the electric starting motor being energized atthe same. time. The direction of coiling of the spring 6 is so arrangedwith respect to the direction of rotation of the shaft 1, that as soonas the pinion 2 meshes with the crown wheel 5, an energetic automatictightening of the said spring upon the shaft 1 is effected so that theelectric motor drives the pinion 2 and crown wheel 5 and the internalcombustion engine is started. As soon as the engine rotates, under itsown power, the clamping effect of the spring 6 upon the shaft 1 becomesreduced and finally when the crown wheel 5 commences to drive the pinion2, the spring 6 forms a free wheel device which avoids any damage to thetransmission before the pinion 2 has been disengaged by the manipulationof the fork controlling the said pinion.

The section and length of the spring 6 are selected according tocircumstances whilst. means such as a brake may be provided to increase,either permanently or temporarily, the friction of the free end of thespring with the shaft 1. Finally, the operative and return movements of7 the pinion 2 may be brought about by any suitable means other than thefork system described.

It will be also understood that this variation of the inventioncomprises various methods of execution within the scope of theinvention. For example, the strip 6 may be mounted within the casing 4secured to or integral with the pinion 2 which then contacts directlywith the shaft 1.

I claim:

1. A clutch comprising a smooth and uniform driving shaft, a drivenelement upon said shaft, and an elastic means upon said shaft alignedwith said driven element and solely enveloping said shaft, which elasticmeans has one end free and the other end rigidly attached to the drivenelement so that said elastic means is rotatable in one direction withsaid driven element upon said shaft, while -in the other direction theelastic means frictionally grips the shaft and causes both said elasticmeans and the driven element to rotate positively with the shaft, andmeans for axially sliding said driven element together with said elasticmeans along the shaft for the purpose of coupling the driven elementwith a motion transmission system.

2. A spring clutch comprising a smooth and uniform driving shaft, adriven element upon said shaft, and a helical spring upon said shaftaligned with said driven element and solely enveloping the shaft, whichhelical spring has one end free and the end adjacent the driven elementrigidly attached thereto so that the spring is rotatable in onedirection with said driven element upon the shaft, while in the otherdirection said spring frictionally grips the shaft and causes both thespring and the driven element to rotate positively with said shaft, andmeans for axially sliding said driven element together with said helicalspring along the shaft in order to couple the driven element with amotion transmission system.

3. A spring clutch comprising a smooth and uniform driving shaft, adriven element upon said shaft, and a flat spiral spring upon said shaft5 aligned with said driven element and solely enveloping the shaft,which flat spiral spring has one end free and the other end rigidlyattached to said driven element so that the spring is rotat able in onedirection with said driven element

